任何人都可以帮我一些Angular的承诺吗?我有以下函数应该接受一个文件对象数组,迭代它们,并上传每一个.在每次迭代期间,promise对象被推送到promises数组.在我的上传函数中,我有一个附加.then()的循环函数,在所有promise对象都已解析之前不应该调用它.我认为我的代码看起来是正确的,但它无法正常工作.图像上传,但是立即调用循环(文件).then(),而不是一旦promises数组结算.
function upload(files) { var uploadCount = files.length; function cycle(files) { var promises = []; for (var i = 0; i < files.length; i++) { var deferred = $q.defer(); promises.push(deferred); var file = files[i]; Upload.upload({ url: '/photos.json',file: file }).success(function(){ $scope.progressCurrentCount += 1; deferred.resolve(); }); }; return $q.all(promises); }; cycle(files).then(function(result) { if(uploadCount > 1) { $scope.lastAction = 'uploaded ' + uploadCount + ' photos'; } else { $scope.lastAction = 'uploaded ' + uploadCount + ' photo'; } $scope.showSuccessModal = true; $scope.uploading = false; $scope.FailedUploads = []; $scope.newPhotos = { token: $scope.token,files: undefined }; photoUploadBtn.removeClass('disabled'); }) };
最终工作代码*
而不是设置var deferred = $q.defer();将deferred.promise推入promises数组,然后在我的.success()回调中解析延迟,这不起作用,我只是将我的Upload.upload()函数推送到promises中而没有.success()回调,然后传递到$q.all(),它完成所有提升.
function upload(files) { var uploadCount = files.length; function cycle(files) { var promises = []; for (var i = 0; i < files.length; i++) { var file = files[i]; var promise = Upload.upload({ url: '/photos.json',file: file }); promises.push(promise); }; return $q.all(promises); }; cycle(files).then(function(result) { if(uploadCount > 1) { $scope.lastAction = 'uploaded ' + uploadCount + ' photos'; } else { $scope.lastAction = 'uploaded ' + uploadCount + ' photo'; }; $scope.showSuccessModal = true; $scope.uploading = false; $scope.FailedUploads = []; $scope.newPhotos = { token: $scope.token,files: undefined }; photoUploadBtn.removeClass('disabled'); getPhotos(q); }) };
解决方法
你必须将promise,而不是deferred,推送到promises数组:
promises.push(deferred.promise);
如果您这样考虑它会有所帮助:
> promise是您想要返回给消费者的只读对象> deferred是该只读承诺的修饰符,您希望自己保留它
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